This invention relates generally to integrated circuits including integrated circuits with passive components such as inductors or capacitors and integrated circuits with active elements such as transistors.
A variety of integrated circuits may include passive components such as inductors or capacitors. For example, radio frequency circuits utilized in connection with radio transceivers or cellular telephones may include both logic elements, mixed signal elements and analog elements.
In some cases, noise or electromagnetic interference produced by the passive or active components may interfere with the operation of other passive or active components or components formed in the same substrate with the passive components. For example, complementary metal oxide semiconductor structures may be formed that define logic elements as well as radio frequency elements having passive components. Integrated capacitors or inductors may be formed over the same substrate that includes logic elements. The substrate may be formed of silicon or germanium material as examples.
In many cases, the high frequency radio frequency devices may be formed on separate integrated circuits to avoid interference between logic devices and components that operate in radio frequency range. This avoids the problem of noise being coupled through the substrate. However, using separate integrated circuits significantly increases the cost of the combined circuitry. Integration of more components into the same integrated circuit generally reduces costs. Moreover, integration into the same circuit normally also results in higher performance.
Thus, there is a need for techniques that facilitate the formation of active and passive circuit components, operating for example a high frequencies, on the same semiconductor substrate that also includes other components such as logic devices.